Question
Oak Tree w/soft spongy
We have a very old oak tree in our back yard that appears healthy. We noticed a spongy area on the trunk where the bark has fallen off. (See attached pictures.) Can you tell what is causing this? We love this tree and want to keep it!
Thanks
AnswerLooks like borer damage and a decay fungi has entered the wound. The decay fungi will over a long time possibly decay the wood inside the tree trunk but will not cause any real health problems unless the decay get high into the trunk and then limbs could break off. IF this happens this will be many many years down the road. There is not any treatment that will rid the tree of the decay fungi--keeping it healthy will go a long way to slow the decay.
The borers need to be controlled. I would recommend that you spray the area of the trunk with dark spots with an insecticide called Onxy or Merit. Check with your local garden type store for these insecticides. Borers attack trees under stress so I would fertilize the tree with 10-10-10 fertilizer at the rate of 1 lb per inch of trunk diameter scattered around the tree and watered in good. Apply the fertilizer just before a rain storm and you will not need to water. This will increase the health of the tree to ward off the borers and the decay.
